S&S Pinion Gear Under Size For Harley Softail / Touring Features: Undersize pinion gear Measurement of gear lash must be between .0005 and .002. If backlash is not present, or if is less than .0005, the pinion gear must be replaced with an undersized pinion gear 10213265. If the backlash is greater than .002 the pinion gear must be replaced with an oversized pinion gear 10213267